One way to think of infection control best practice with needles like this.

The cost of a new needle, syringe or new gloves is quite cheap.

The cost of an infection is high.

The cost of a HIV infection is life altering.

So, its clear that whoever did this thought that whatever small savings they obtained from not using a fresh syringe was more important to them than the high likelihood their patients would get infections, including HIV.

Your cost claims need to be considered with the perspective of the country or location of the clinic.